Thunderbolt 3

[Ryan Carlson]

QNAP's webpage says that speed drops by half if directly connected to NAS. Why is this and how can I
maximize Thunderbolt 3 speed? Considering direct connect between TS-453BT3 and Microsoft laptops. Thank you.

 

[L&LD]

QNAP's webpage says that speed drops by half if directly connected to NAS. Why is this and how can I
maximize Thunderbolt 3 speed? Considering direct connect between TS-453BT3 and Microsoft laptops. Thank you.

Link? To the QNAP page that states that?

 

[Ryan Carlson]

Hopefully I'm mistaken, but here is the link and text I was referring too.

https://www.qnap.com/solution/thunderbolt3-nas/en-us/


"Note:
1. Directly connecting a QNAP Thunderbolt 3 NAS to a computer establishes a peer-to-peer (P2P) network and enables 20GbE connectivity."

 

[L&LD]

Hopefully I'm mistaken, but here is the link and text I was referring too.

https://www.qnap.com/solution/thunderbolt3-nas/en-us/


"Note:
1. Directly connecting a QNAP Thunderbolt 3 NAS to a computer establishes a peer-to-peer (P2P) network and enables 20GbE connectivity."

Good news! I think you were mistaken.

How I'm reading it is that the TB3 40Gbps connectivity drops to 20GbE connectivity (i.e. 'half').

I think you'll still be far ahead.

 

[Ryan Carlson]

In breaking through the slow ethernet barrier, I see the biggest drawback to TB3 is the 6ft cord length. Right? Yes, one can daisy chain, but more $$ and franky cumbersome. TB2 is available in longer lengths, but half speed. With 10GBe, I hear the sound of crickets in in ports. As a non-tech person aiming for a simple, but fast NAS to power thier small business, I am dumbfounded that cables are so important. Please tell me I am wrong. My current plan is to buy QNAP TS-453BT3-8G-US 4-Bay Thunderbolt 3 NAS, but run TB2 cables with adapters because I need the cables to actually reach computers. Any advice appreciated, as always.

 

[L&LD]

In breaking through the slow ethernet barrier, I see the biggest drawback to TB3 is the 6ft cord length. Right? Yes, one can daisy chain, but more $$ and franky cumbersome. TB2 is available in longer lengths, but half speed. With 10GBe, I hear the sound of crickets in in ports. As a non-tech person aiming for a simple, but fast NAS to power thier small business, I am dumbfounded that cables are so important. Please tell me I am wrong. My current plan is to buy QNAP TS-453BT3-8G-US 4-Bay Thunderbolt 3 NAS, but run TB2 cables with adapters because I need the cables to actually reach computers. Any advice appreciated, as always.

Yes, the cables are very important as are their maximum specified lengths.

When important data is moving at these speeds, the quality trumps the cost every time. Without reliability/stability, the cost savings are for naught.

In your position, I would be considering re-arranging the office so that you can connect two computers via TB3 with each TS-453BT3 you're buying. If possible, of course.

I would not waste any time with daisy chaining them either. I would rather buy a TS-453BT3 or slightly lower end equivalent for each user is speed/performance is your end goal.

From the QNAP information page for the TS-453BT3:

Thunderbolt 3 reaches the maximum theoretical transfer rate of 40 Gigabits per second. Actual performance may vary due to hardware/software limitations and usage environment. Directly connecting a QNAP Thunderbolt 3 NAS to a computer establishes a peer-to-peer (P2P) network and enables 20GbE connectivity.

The above reinforces what I originally understood.

It also shows that running any daisy chain will degrade that performance even further (from imperceptible, to too much, depending on the implementation).

Can you re-arrange the office? Face two or more desks together in an 'open' area? Or, put two desks on either side of a wall and punch through it for the TB3 cables to connect with? The goal here is to connect each computer with a single TB3 cable directly to the TS-453BT3, of course. If this isn't feasible, then I would not proceed.

How many users in total need this kind of storage performance? Would multiple (mirrored) TS-453BT3 work better (for a given budget and immovable workspaces)?

Note that the QNAP specs show lower performance on TB3 on an MBP than on a 10GbE connection. See the graphs in the following link.

https://www.qnap.com/en/product/ts-453bt3

The above testing was also done with 4 SSD's in RAID0 on an 8GB RAM TS-453BT3 and the 10GbE testing was on an i7-6700 desktop with 32GB RAM.

These kinds of speed need a lot of computing horsepower. That power comes only with buckets of cash.

 

[Ryan Carlson]

Good questions and I agree the speed tests are based on serious power and cost, yet desks cant really move.
The goal here is indeed to connect each computer with a single TB3 cable directly to the TS-453BT3.
I'll have to sit on this decision. Thank you for your good advice.

 

[System Error Message]

It looks like if it detects another host, it uses the 20GbE setting as a network adapter instead, which could be a limiting factor in how the bandwidth is given, it may not be the cable, just the interface and protocol.

Thunderbolt has many modes too. however if you can connect 2 PCs to the same NAS you would be able to get the max 40Gb/s but you also have to look at your NAS's architecture, if it has 2 thunderbolt ports are they sharing the same bandwidth/how many PCIe lanes to CPU. The limiting factor that a decent number of thunderbolt 3 ports get is that they are connected via the chipset and so have to share bandwidth with everything else, this was tested on laptops for comparing against the alienware AGA that was a CPU x4 PCIe interface and found that even with the full x4 PCIe 3 interface of thunderbolt 3, it can sometimes cause issues from the bus bottleneck between the CPU and chipset when you have a lot of bandwidth potential between storage and other things too.

 

[Ryan Carlson]

That was hard terminology for me to understand. I'm not tech savvy. For example interface, protocols, architecture, chip set and bus bottleneck. For the QNAP TS-453BT3 in particular does it share bandwidth between its two TB3 ports and does it have PCIe interface limitations?

 

[System Error Message]

That was hard terminology for me to understand. I'm not tech savvy. For example interface, protocols, architecture, chip set and bus bottleneck. For the QNAP TS-453BT3 in particular does it share bandwidth between its two TB3 ports and does it have PCIe interface limitations?

most likely, chipsets that have thunderbolt 3 do get the full x4 bandwidth, sometimes the 2 ports are shared sometimes not, but sometimes they can be a chip added via PCIe. You'll have to check the chipset it uses and see what it has, that will tell you whether each port is limited or shared. If you see no TB3 on the chipset, but PCIe lanes, thats what the thunderbolt will use most of the time. With thunderbolt 3 i would not worry about how many ports there are because you can daisy chain them, and if the single TB3 port has full bandwidth, you could daisy chain 2 PCs and get the full bandwidth if both PCs are addressed directly by the NAS rather than one of the PCs being a switch to the other.

Look at the chipset it uses, it will tell you lots. If its 1 TB3 port most likely the 2 are sharing the same bandwidth. If its just a PCIe x4 on the chipset, then each one is connected via 2 lanes to the chipset. For a NAS the chipset isnt much of a bottleneck thanks to DMA on drives, so this means that the TB3, PCIe, NICs can transfer data between drives without going through the CPU. If connecting to PC is limited to half bandwidth, but you have 2 (doesnt matter if shared as long as they have full connectivity to chipset), then you can fully use the bandwidth.

For TB3, if you have 2 TB3 ports sharing the same TB3 connection to the chipset, then even just 1 can use the full bandwidth thanks to modes and protocols, but doesnt change the fact that the method used by qnap to talk to PCs is using only half the bandwidth per PC.